2016-04 Security Bulletin: ScreenOS: Malformed SSL/TLS packet causes Denial of Service (CVE-2016-1268)Product Affected:This issue affects any products and platforms running ScreenOS versions 6.3.0r19b and earlier releases.
Problem:A specially crafted malformed packet received on any interface targeted to the device’s administrative web services interface may cause loss of administrative access to the system and can reboot the system causing a complete denial of service.This issue does not affect SSH administrative services interface and is not vulnerable to malformed transit traffic.Crafted broadcast and multicast traffic does not affect the device.Other services operating SSL/TLS services are not affected by a directly targeted crafted malformed packet.This issue was discovered by an external security researcher.No other Juniper Networks products or platforms are affected by this issue.This issue has been assigned CVE-2016-1268.
Solution:The following software releases have been updated to resolve this specific issue: ScreenOS 6.3.0r21 and all subsequent releases.This issue is being tracked as PR 1123333 and is visible on the Customer Support website.KB16765 – “In which releases are vulnerabilities fixed?” describes which release vulnerabilities are fixed as per our End of Engineering and End of Life support policies.
Workaround:Methods to reduce the risk associated with this issue include:Limit access to SSL ports to only trusted hosts.
Disabling web administrative services will mitigate the risk of this issue.
unset int eth0/0 manage web
Refer to KB6713 for enabling SSH on the firewall.
In addition to the recommendations listed above, it is good security practice to limit the exploitable attack surface of critical infrastructure networking equipment. Use access lists or firewall filters to limit access to the device via the network only from trusted, administrative networks or hosts.
Implementation:How to obtain fixed software:ScreenOS software releases are available at http://www.juniper.net/support/downloads/screenos.htmlModification History:
2016-04-13: Initial publication
Related Links:CVSS Score:7.5 (CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)
Risk Assessment:Information for how Juniper Networks uses CVSS can be found at KB 16446 “Common Vulnerability Scoring System (CVSS) and Juniper’s Security Advisories.”
Acknowledgements:Juniper SIRT would like to acknowledge and thank Marcel Bilal www.itdz-berlin.de for responsibly reporting this vulnerability.